Yaniv Kaul
2018-Feb-06 09:52 UTC
Re: [Libguestfs] [ovirt-users] Slow conversion from VMware in 4.1
On Feb 6, 2018 11:06 AM, "Luca 'remix_tj' Lorenzetto" < lorenzetto.luca@gmail.com> wrote: On Mon, Feb 5, 2018 at 11:13 PM, Richard W.M. Jones <rjones@redhat.com> wrote:> http://libguestfs.org/virt-v2v.1.html#vmware-vcenter-resources > > You should be able to run multiple conversions in parallel > to improve throughput. > > The only long-term solution is to use a different method such as VMX > over SSH. vCenter is just fundamentally bad.4 conversions in parallel works, but each one is very slow. But i think i've to blame vcenter cpu which is stuck at 100%. I assume its network interfaces are also a bottleneck as well. Certainly if they are 1g. Y. Thank you for the directions and suggestions, Luca -- "E' assurdo impiegare gli uomini di intelligenza eccellente per fare calcoli che potrebbero essere affidati a chiunque se si usassero delle macchine" Gottfried Wilhelm von Leibnitz, Filosofo e Matematico (1646-1716) "Internet è la più grande biblioteca del mondo. Ma il problema è che i libri sono tutti sparsi sul pavimento" John Allen Paulos, Matematico (1945-vivente) Luca 'remix_tj' Lorenzetto, http://www.remixtj.net , < lorenzetto.luca@gmail.com> _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
Luca 'remix_tj' Lorenzetto
2018-Feb-06 10:11 UTC
Re: [Libguestfs] [ovirt-users] Slow conversion from VMware in 4.1
Il 6 feb 2018 10:52 AM, "Yaniv Kaul" <ykaul@redhat.com> ha scritto: I assume its network interfaces are also a bottleneck as well. Certainly if they are 1g. Y. That's not the case, vcenter uses 10g and also all the involved hosts. We first supposed the culprit was network, but investigations has cleared its position. Network usage is under 40% with 4 ongoing migrations. Luca
Richard W.M. Jones
2018-Feb-06 10:19 UTC
Re: [Libguestfs] [ovirt-users] Slow conversion from VMware in 4.1
On Tue, Feb 06, 2018 at 11:11:37AM +0100, Luca 'remix_tj' Lorenzetto wrote:> Il 6 feb 2018 10:52 AM, "Yaniv Kaul" <ykaul@redhat.com> ha scritto: > > > I assume its network interfaces are also a bottleneck as well. Certainly if > they are 1g. > Y. > > > That's not the case, vcenter uses 10g and also all the involved hosts. > > We first supposed the culprit was network, but investigations has cleared > its position. Network usage is under 40% with 4 ongoing migrations.The problem is two-fold and is common to all vCenter transformations: (1) A single https connection is used and each block of data that is requested is processed serially. (2) vCenter has to forward each request to the ESXi hypervisor. (1) + (2) => most time is spent waiting on the lengthy round trips for each requested block of data. This is why overlapping multiple parallel conversions works and (although each conversion is just as slow) improves throughput, because you're filling in the long idle gaps by serving other conversions. This is also why other methods perform so much better. VMX over SSH uses a single connection but connects directly to the ESXi hypervisor, so cause (2) is eliminated. VMX over NFS eliminates VMware servers entirely and can make multiple parallel requests, eliminating (1) and (2). VDDK [in ideal circumstances] can mount the FC storage directly on the conversion host meaning the ordinary network is not even used and all requests travel over the SAN. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/
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